Dandelion - Reading Assignment

[kylemoore8]

1. A propagation technic of transactions in the P2P network.

2. STEM phase is called the process of looking for a proxy node to broadcast.
   FLUFF phase is the process of broadcasting to the network.

3. Dandelion does not resist adversaries seeking to link transactions with IP addresses not following the rules of the network.

4. Epochs or fail safe

[Uyan]

1. Flooding is a method of broadcasting transmissions throughout the network. A node broadcast its transaction to its peers, with each of those peers broadcasting to their peers, and so on.

2. A Dandelion broadcast has 2 phases: the stem phase and the fluff phase:

• Stem (Anonymity) Phase: a process for finding a proxy node to broadcast from.
• Fluff Phase: spreading the transaction/information rapidly and symmetrically.

3. With Dandelion, a botnet participating honestly in the P2P network cannot reliably link transactions with IP addresses

A malicious botnet, on the other hand, could link transactions with IP addresses. It is this issue that Dandelion++ aims to address.

4. Under the Dandelion++ protocol, there are 2 ways to transition from the stem phase to the fluff phase:

• For each epoch [an epoch typically lasts around a few minutes], a node classifies itself as either a relayer or a diffuser. The mode is determined at random at the start of the epoch. If a node is a diffuser, whenever it is given a transaction to relay as stem phase, it instead broadcasts it using diffusion, thereby starting the fluff phase.

• If a time threshold passes without the node receiving the same transaction back during a fluff phase, it starts its own fluff phase. This serves two purposes: It frustrates attempts at deanonymization using timing, and it defeats so-called black-hole attacks where adversarial nodes discard transactions during the stem phase rather than relaying them.

[Dani_Kavcic]

1. “Flooding” is a term used when a node starts broadcasting of a new tx.

2. Anonymity and spreading. Anonimity defines a process for finding proxy node to broadcast. Spreading is second phase where the proxy node spreads information rapidly and symmetrically.

3. Dandelion++ works on fixing the problem of trustlessnes-a node may not be “honest” and could undermine its anonymity.

4. Either by a new epoch, where nodes are classified as relayer(stem) or difuser (fluff). If a time treshold passes after relaying a tx during stem phase and not reciving the same tx back during a fluff phase, in this case the node starts its own fluff phase.

[Alex_Chaz]

1. flooding is broadcasting Tx’s through the network
2. Anonymity or stem phase for finding a proxy node to broadcast
   Spreading or fluff phase, where it spreads the data
3. " With Dandelion, a botnet participating honestly in the P2P network cannot reliably link transactions with IP addresses. "
4. " it proceeds in discreet intervals, called epochs. Each node switches epoch independently, typically every few minutes. With each new epoch, a node picks two new relay connections at random from its outbound connections. Then whenever the node creates its own transaction it sends it over one of these two relays, always making the same choice for a given epoch. And whenever it gets a transaction from another node for forwarding during stem phase, if it is a relayer, it sends it out randomly over one of the two relays. "

[Bull75rm]

1. Flooding is when a node communicates the transaction to all its peers.
2. The two phases of a Dandelion are:
   a. Anonymity (or stem) phase - seeking out a proxy node along a special linear search path
   b. The Spreading (or fluff) phase – After seeking out a proxy node, then from this proxy node spreading the information rapidly and symmetrically
3. Large scale rule breaking deanonymization attacks.
4. Switching the epoch or trough “fail-safe" mechanism.

[LukeS]

1. Flooding is the process of broadcasting new transactions. The starting node Broadcasts to all its peers, and each peer broadcasts to their peers until every node has the transaction.
2. Stem Phase: finds a proxy node to broadcast from. Fluff Phase: broadcasting phase.
3. Helps resist large-scale rule-breaking deanonymization attacks.
4. Within each epoch if a diffuser node is given a transaction it will start the broadcast. OR if a timer for the transaction relays is reached the relayer node will start broadcasting.

[Aiisnotbad]

@Grant_Hawkins

• What is ‘flooding’?
• What are the two phases of a Dandelion broadcast and what happens in each phase?
• What potential weakness of Dandelion does Dandelion++ aim to address?
• Under the Dandelion++ protocol, what are the two ways to transition from the ‘stem’ phase to the ‘fluff’ phase?

. It is a quick spreading of a transaction from each node to all his peers until the network is flooded by the transaction. It is basically a broadcast.

. Stem and fluff phase. The stem phase is basically when a node is looking for a « random VPN »(a random node that will serve as a proxy). The fluff phase is like a broadcast segmented into « randomized timing » for each specific communication.

. It addresses a bizantine fault where a lot of nodes are either faulty or malicious.

. The first way to transition is for the node to randomly choose between the relay or diffuser mode at each epoch. This is set by a percentage property in the code. The other way is when the node is in relay mode and does not receive a confirmation from any other relays. The node then switches to spreading mode.

[mervxxgotti]

1. What is ‘flooding’? — redundant communication by broadcasting transactions to all peers, then that peer to all peers and so on, travelling in all directions
2. What are the two phases of a Dandelion broadcast and what happens in each phase? Anonymity or stem phase to seek out a proxy node along a special linear search path then spreading or fluff phase where proxy node spreads information rapidly and symmetrically in a flood
3. What potential weakness of Dandelion does Dandelion++ aim to address? — dandelion++ is able to resist large scale rule breaking deanonymization attacks
4. Under the Dandelion++ protocol, what are the two ways to transition from the ‘stem’ phase to the ‘fluff’ phase? By epoch switching or through a fail safe mechanism

[Nicksta]

1. The information travels in all directions over the network like a wave. Flooding the network

2. In general, the two phases use different sets of peer connections with the important difference that the anonymity phase connection set changes with time. Phase 1 (stem) : finds a proxy node for the initial broadcast of the transaction and phase 2 (fluff): The node spreads the information rapidly and symmetrically throughout the network

3. Dandelion++ tweaks Dandelion to resist large-scale rule-breaking deanonymization attacks. It creates an additional node relay in the stem phase. Making it hard to link IP addresses and transactions.

4. In the new stem phase, to implement dynamic connectivity, it proceeds in discreet intervals, called epochs. With each new epoch, a node picks two new relay connections at random from its outbound connections. Then whenever the node creates its own transaction it sends it over one of these two relays, always making the same choice for a given epoch. And whenever it gets a transaction from another node for forwarding during stem phase, if it is a relayer (more on this below), it sends it out randomly over one of the two relays.

[Zulu1]

• What is ‘flooding’? It’s the start of a new transaction broadcasted in all direction over the network. Where the transaction is communicate to all its peers, who in turn communicate to all their peers, with some checks to prevent redundant communication

• What are the two phases of a Dandelion broadcast and what happens in each phase? The phases are the anonoymity (stem) phase and the spreading (fluff) phase. The difference is that the anonymity phase uses a proxy node and the connection set changes with time.

• What potential weakness of Dandelion does Dandelion++ aim to address? The weakness of large scale rule breaking deanonymization attacks.

• Under the Dandelion++ protocol, what are the two ways to transition from the ‘stem’ phase to the ‘fluff’. The stem phase use dynamic connectivity and it proceeds in discreet intervals called epoch. For each epoch a node classifies itself as either a relayer or a diffuser, the nodes are determined at random at the start of each epoch. The node could also trigger the fluff phase.

[vegas316]

1. What is ‘flooding’?
Flooding is a process of distributing transactions where the transaction is sent to all the connected peers of a node, and then further to the peers os peers, until it reaches a miner and is added into a block.
2. What are the two phases of a Dandelion broadcast and what happens in each phase?
Stem and Fluff. Stem finds a proxy node to distribute the transaction, and the fluff phase symetrically distributes the transaction.
3. What potential weakness of Dandelion does Dandelion++ aim to address?
Dandelion is only effective against passive advasaries on the network. Dandelion++ is designed to thwart active adversaries on the network.
4. Under the Dandelion++ protocol, what are the two ways to transition from the ‘stem’ phase to the ‘fluff’ phase?

1. If, at the beginning of an epoch, a node classifies itself as a diffuser, then it will start the fluff phase when it is sent a message to relay
2. If, at the beginning of an epoch, a node classifies itself as a relayer, and sends a message, but does not receive a copy of the message as a diffusion after a certain time period, then it will start the diffusion (fluff) phase.

[ol_frank]

1. What is ‘flooding’?
   Flooding is the process of broadcasting your transaction to all local nodes at the same time. these nodes then propagate the said transaction to its local nodes at the same time creating a wave like sequence.

2. What are the two phases of a Dandelion broadcast and what happens in each phase?
   The Stem phase finds a proxy node to broadcast the transaction. The fluff phase establishes another process for broadcast distributing the transaction further.

3. What potential weakness of Dandelion does Dandelion++ aim to address?
   Dandelion++ resists large-scale rule breaking deanonymising attacks from passive observer nodes

4. Under the Dandelion++ protocol, what are the two ways to transition from the ‘stem’ phase to the ‘fluff’ phase?
   The first is: (Diffuser Node) whenever it is given a transaction to relay as stem phase, it instead broadcasts it using diffusion, thereby starting the fluff phase.
   The second is: (Relay Node) it sends a transaction randomly over one of the two relays.

[Samuel1]

1. Flooding is a broadcasting process used to communicate transactions across the network, by having all nodes communicating the information to their peers.
2. The two phases of a Dandelion broadcast:
   1 Anonymity- seeking out a proxy node along a special linear search path
   2Spreading-spreading information of proxy node rapidly and symmetirically
   3.The potential weakness of Dandelion is that of honesty amongst nodes, thus undermining Dandelion’s anonymity.
3. The two methods are:

• “epochs switching”
• “fail-safe mechanism”

[HemalT]

What is ‘flooding’?
It is a broadcasting process used to communicate transactions across the network, by having all nodes communicating the information to their peers which will then do the same and so on, so forth

2. What are the two phases of a Dandelion broadcast and what happens in each phase?
   STEM phase is called the process of looking for a proxy node to broadcast
   FLUFF phase is the process of broadcasting (or spreading) to the network

3. What potential weakness of Dandelion does Dandelion++ aim to address?
   The risk that nodes within the network may not be “honest” nodes and undermine Dandelion’s anonymity

4. Under the Dandelion++ protocol, what are the two ways to transition from the ‘stem’ phase to the ‘fluff’ phase?
   Either by using the “epochs switching” method or through the “fail-safe mechanism”

[Toddness]

1. What is ‘flooding’? The process a node uses to broadcast a new transaction to its peers, and then those peers tell their peers etc.

2. What are the two phases of a Dandelion broadcast and what happens in each phase? Anonymity or Stem phase. Finding a proxy node on a linear search path.

Spreading or fluff phase. Spreading rapidly and symmetrically.

3. What potential weakness of Dandelion does Dandelion++ aim to address? To resist large-scale rule-breaking deanonymization attacks. That is cancel out nodes who don’t use Dandelion or nodes that don’t follow the rules.

4. Under the Dandelion++ protocol, what are the two ways to transition from the ‘stem’ phase to the ‘fluff’ phase? If a node is a diffuser, whenever it is given a transaction to relay as stem phase, it instead broadcasts it using diffusion, thereby starting the fluff phase. It also has a fail safe mechanism to invoke.

[maxs]

1. What is ‘flooding’?
   Flooding is the process where a Monero node starts the broadcast of a new transaction.

2. What are the two phases of a Dandelion broadcast and what happens in each phase?
   -Anonymity (or stem) phase: finding a proxy node to broadcast
   -Spreading (or fluff) phase: broadcast

3. What potential weakness of Dandelion does Dandelion++ aim to address?
   Large-scale rule-breaking deanonymization attacks, where adversaries have spy nodes distributed throughout the network, forming some significant fraction of the overall network.

4. Under the Dandelion++ protocol, what are the two ways to transition from the ‘stem’ phase to the ‘fluff’ phase?
   -Epoch switching
   -Fail-safe mechanism

[Denzel]

1.- Broadcasting a transaction to the rest of the nodes.

2.- Anonymity phase: Finding a proxy node to broadcast.
Spreading phase: Spreading info through said node.

3.- Delay to transaction propagation.

4.- With Epochs and difussion.

[walter_w]

1. sending the tx to all nodes, who in turn send to their nodes
2. Anonymity: finding a node to broadcast to. Spreading: having that node broadcast
3. dishonest nodes attempting to identify the users
4. when a diffuser receives a broadcast it originally sent out or if the relay node time threshold is passed

[Meddodreddo]

1. What is ‘flooding’?
   Flooding is the manner in which a Monero node broadcasts a new transaction to other nodes, it has an origin and a time dependent arrival at other nodes which isn’t controlled. So it creates a pattern which can be observed and back calculated to identify the originating node.

2. What are the two phases of a Dandelion broadcast and what happens in each phase?
   -Route transactions to a remote node first- anonymity/stem phase
   -spreading/fluff phase

3. What potential weakness of Dandelion does Dandelion++ aim to address?
   Resistant to passive observers ona network of honest nodes, but doesn’t protect from active observers with dishonest nodes…D++ is resistant to large scale deanonymization attacks

4. Under the Dandelion++ protocol, what are the two ways to transition from the ‘stem’ phase to the ‘fluff’ phase?
   One of two modes picked at random at the start of each epoch: relayer or diffuser mode
   If in diffuser mode, it will start a fluff phase even if it was a relayer in the stem phase. So: 1. A relay node can epoch switch to diffuser and start the fluff phase. 2. A relay node can “time out” when awaiting a return on the relayed transaction, so will initiate a fluff phase (fail-safe mechanism)

[Fjell]

1. 'Flooding’ is when a Monero node starts the broadcast of a new transaction. It communicates the transaction to all its peers, who in turn communicate to all their peers, and so forth, with some checks to prevent redundant communication. The information travels in all directions over the network like a wave. Some cryptocurrencies, like Bitcoin, randomize the timing of this broadcast, but Monero does not.
2. The two phases of a Dandelion broadcast are firstly a process for finding a proxy node to broadcast the flooding, called the anonymity (or stem) phase. Secondly it establishes another process for broadcast, called the spreading (or fluff) phase. In general, the two phases use different sets of peer connections with the important difference that the anonymity phase connection set changes with time.
3. The potential weakness of Dandelion which Dandelion++ aims to address is that an adversary seeking to link transactions with IP addresses may not be passive, and may not follow the rules of the network. So the creators of Dandelion++ modeled an adversary as a botnet with spy nodes distributed throughout the network, forming some significant fraction of the overall network. In their model, these nodes need not follow the rules. They can generate any number of outbound connections to any honest or adversarial nodes. They use all available information, including timing and the addresses of senders. It is in this very hostile environment that Dandelion++ succeeds in protecting anonymity.
4. Under the Dandelion++ protocol, the two ways to transition from the ‘stem’ phase to the ‘fluff’ phase are that in the new stem phase, to implement dynamic connectivity, it proceeds in discreet intervals, called epochs. Each node switches epoch independently, typically every few minutes. With each new epoch, a node picks two new relay connections at random from its outbound connections. Then whenever the node creates its own transaction it sends it over one of these two relays, always making the same choice for a given epoch. Additionally,whenever it gets a transaction from another node for forwarding during stem phase, if it is a relayer node, it sends it out randomly over one of the two relays.